Between the mid-1860s and the early 1880s, the Prussian and later Imperial German Navies purchased or built sixteen ironclad warships. In 1860, however, the Prussian Navy consisted solely of wooden, unarmored warships. The following year, Prince Adalbert and Albrecht von Roon wrote an expanded fleet plan that included four large ironclads and four smaller ironclads. Two of the latter were to be ordered from Britain immediately, as German shipyards were at the time incapable of building such vessels. The rival Danish fleet had three ironclads in service by the time the Second Schleswig War broke out in 1864; as a result, Prussia purchased the ironclads Arminius and Prinz Adalbert, then under construction in Britain and France, respectively. The British, sympathetic to the Danish cause, dela